Method of and apparatus for enveloping moving articles

Abstract

In order to envelop the necks of a series of continuously moving bottles with decorative or informative tubular attachments, an elongate tube of heat-shrinkable plastic material is flattened first in one longitudinal plane and then in another longitudinal plane, perpendicular to the former, to produce a sheath with two substantially flat sides bearing the traces of a first pair of creases while being bounded by a second pair of creases. The longitudinally advancing sheath is cut into clippings of predetermined length that are advanced codirectionally therewith but at higher speed along a sloping guidepath in which the existing creases are caused to converge while the original creases reappear as the two sides are progressively spread apart. At a point where the creases of the two pairs are separated by substantially the same distance at a leading end of a clipping, the latter meets the neck of an oncoming bottle at an obtuse angle to its direction of motion whereby a remote edge of that leading end is engaged and tilts the clipping into a vertical position in which it slides down the neck. A subsequent heat treatment shrinks the clipping around that neck as a tightly fitting collar or jacket.

I claim: 
     
       1. A method of fitting a series of continuously moving support elements with tubular attachments enveloping same at least in part, comprising the steps of: (a) providing a flattened deformable sheath of indefinite length having two major sides bounded by a pair of longitudinal creases, said sides being separable from each other in a transverse direction;   (b) advancing said sheath along a guidepath descending toward a row of said moving support elements;   (c) cross-cutting the advancing sheath at an intermediate point of said guidepath into successive clippings of predetermined length;   (d) advancing each freshly cut clipping at a higher speed than said sheath along a stretch of said guidepath narrowing in an axial plane including said creases, with resulting progressive separation of said sides from each other until their spacing in said transverse direction substantially equals the distance between said creases at a leading end of the clipping; and   (e) discharging each descending clipping from said guidepath at an obtuse angle to the direction of motion of said support elements at a level at which a remote edge of the leading end thereof is met by an upright part of an oncoming support element with a cross-sectional area smaller than that of said leading end whereby the descending clipping is erected and comes to rest around said upright part.   
     
     
       2. A method as defined in claim 1 wherein step (a) includes an initial flattening of said sheath to form a pair of fold lines in a plane perpendicular to said axial plane, followed by a reflattening of said sheath in said axial plane to form said major creases while leaving only traces of said fold lines midway on the major sides bounded by said creases, said fold lines reappearing in step (d) and defining with said creases the lateral faces of a generally tetrahedral body with a cross-sectional area progressively increasing in the direction of advance. 
     
     
       3. A method as defined in claim 1 or 2 wherein said support elements are erect articles traveling in a substantially horizontal line of motion beneath a discharge end of said guidepath. 
     
     
       4. A method as defined in claim 3 wherein said sheath consists of heat-shrinkable plastic material, comprising the further step of subjecting each of said articles beyond its point of encounter with a descending clipping to a heat treatment for shrinking such clipping around the part enveloped thereby. 
     
     
       5. A method as defined in claim 1 or 2 wherein said support elements are intermediate carriers moving along a closed trajectory tangent to a substantially horizontal line of motion of erect articles with necks to be enveloped by said clippings, the motions of said carriers and said articles being synchronized to facilitate a transfer of each clipping from any of said carriers to the neck of a respective article. 
     
     
       6. A method as defined in claim 5 wherein said sheath consists of heat-shrinkable plastic material, comprising the further step of subjecting each of said articles beyond its point of contact with a transferred clipping to a heat treatment for shrinking such clipping around the neck enveloped thereby. 
     
     
       7. In an apparatus for fitting a succession of movable support elements with tubular attachments enveloping at least parts of said support elements, including supply means for paying out a flattened deformable sheath of indefinite length with two transversely separable major sides bounded by a pair of longitudinal creases, transport means for advancing said sheath along a predetermined path, and cutter means for sectioning the advancing sheath perpendicularly to said creases into clippings of uniform length expandable transversely to said major sides, the improvement wherein said path is defined downstream of said cutter means by a pair of guide members with crease-engaging zones converging in the direction of advance, said transport means comprising a pair of counterrotating feed rollers engageable with said major sides at a location upstream of said cutter means and a driver positively engageable with said clippings in the region of said guide members for advancing said clippings between said converging surfaces at a speed higher than the peripheral speed of said feed rollers, said converging zones being separated from each other at a discharge end of said path by a distance related in a ratio of approximately 1:√2 to the distance separating said converging zones in the vicinity of said cutter means whereby a clipping exiting from said path has a leading end of substantially square configuration.   
     
     
       8. An apparatus as defined in claim 7 wherein said converging zones are formed by V-grooves in said guide members widening progressively in the direction of advance. 
     
     
       9. An apparatus as defined in claim 8 wherein said guide members are parallel to each other, said V-grooves being of progressively decreasing depth in the direction of advance. 
     
     
       10. An apparatus as defined in claim 9 wherein said driver comprises a pair of parallel flight conveyors disposed between said guide members with runs each closely adjoining a flank of a respective V-groove thereof. 
     
     
       11. An apparatus as defined in claim 10 wherein said flight conveyors are internally toothed endless bands wound about coaxial pairs of first notched pulleys close to said cutter means and second notched pulleys close to said discharge end, said transport means further including an additional roller coaxially interposed between said first pulleys and a counterroller coacting with said additional roller, said additional roller being of larger diameter than said first pulleys, said bands carrying flights which project close to the circumference of said additional rollers on passing around said first pulleys. 
     
     
       12. An apparatus as defined in claim 7, 8, 9, 10 or 11 wherein said supply means comprises a reel paying out said sheath in the form of a flattened tubing bounded by a pair of fold lines in a first longitudinal plane transverse to the axes of said feed rollers, a first pair of guide rollers on opposite sides of said first longitudinal plane bracketing said tubing between them, and a second pair of guide rollers between said first guide rollers and said feed rollers with axes parallel to those of said feed rollers for reflattening said tubing in a second longitudinal plane perpendicular to said first longitudinal plane to form said longitudinal creases while substantially suppressing said fold lines. 
     
     
       13. An apparatus as defined in claim 12, further comprising a third pair of guide rollers parallel to said second pair of rollers and interposed between the latter and said first pair of rollers, the rollers of said third pair being spaced apart in said second longitudinal plane by a polyhedral core with mutually skew upstream and downstream edges respectively parallel to and inserted between the rollers of said first and second pairs, said sheath passing around said core between said first, second and third pairs of rollers. 
     
     
       14. An apparatus as defined in claim 7, 8, 9, 10 or 11, further comprising drive means for continuously advancing the support elements to be fitted with said attachments at a level below said transport means, said guide members sloping toward said level at an obtuse angle to the direction of motion of said support elements to facilitate a deposition of each discharged clipping on a receiving part of an oncoming support element. 
     
     
       15. An apparatus as defined in claim 14, further comprising stationary guide means extending in the direction of motion of said support elements beyond the discharge end of said path for camming a clipping deposited on any of said elements into a firm enveloping position thereon. 
     
     
       16. An apparatus as defined in claim 14, further comprising sensing means adjacent a line of motion of said support elements for detecting the approach of each support element to the discharge end of said path and synchronizing the operating rate of said cutter and transport means with the motion of said support elements. 
     
     
       17. An apparatus as defined in claim 14 wherein said drive means includes a transfer wheel rotatable about a horizontal axis, said support elements being peripheral bosses on said transfer wheel positioned to receive said clippings from said discharge end and depositing the received clippings on erect articles passing in a row underneath said transfer wheel in synchronism with the rotation thereof. 
     
     
       18. An apparatus as defined in claim 7, 8, 9, 10 or 11 wherein said cutter means comprises a pair of cylinders on opposite sides of said path counterrotating at the same peripheral speed as said feed rollers, at least one of said cylinders being provided with a peripheral blade extending along a generatrix thereof for contact with the opposite cylinder.